Process for producing humic acid salts with fluidizing solid phase reaction

ABSTRACT

The present invention utilizes a high-speed intensive mixer in a fluidizing-type, solid-phase, neutralization reactor to blend solid-state alkali hydroxide with any humic acid sources. The final product is a dry humic acid salt. The purpose of this innovative method is to eliminate a series of complicated unit operations commonly employed by the traditional process. These removed steps may include dissolving caustic soda, mixing in a paste-like formation, extrusion, granulation, drying, and grinding, etc. The invention contributes to a simplified flowsheet, resulting in sharply reduced equipment investment, plant space, and labor and energy costs. All of these factors coupled with increased productivity will drastically lower the overall production cost. Also, the reduction of dust pollution will greatly minimize the impact in environmental protection and safety issues.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of application Ser. No. 15/731,032 filed on Apr.10, 2017; which claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 62/331,788 filed on May 4, 2016; the entirecontents of both applications are hereby incorporated by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

Traditional methods for production of humic acid salts involvecomplicated unit operations that are costly and usually cause seriousenvironmental issues. This invention uses a high-speed intensive mixerto promote chemical reaction between alkali hydroxide (includingpotassium hydroxide, sodium hydroxide, or ammonium hydroxide solution,etc.) and any substances containing humic acid. The new process quicklymakes a dry product in a solid-phase, fluidized-bed type reactor and canreplace the traditional manufacturing procedure with significantlyhigher efficiency and cost benefits. It also addresses the common publicconcerns on the safety and pollution problems.

This invention uses only a high-speed intensive mixer to produce thesame final products by a single step, completing any of followingchemical reactions:R—COOH+NaOH→R—COONa+H₂OR—COOH+KOH→R—COOK+H₂OR—COOH+NH₄OH→R—COONH₄+H₂O

The basic principle of the present invention is different from thetraditional fluidized bed. The present invention only utilizeshigh-speed agitation, instead of large amounts of gas, to fluidize solidpowder. In practice, one or more alkali hydroxide (including potassiumhydroxide, sodium hydroxide, or ammonium hydroxide solution, etc.) canbe added to react with any humic acid source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a caustic humate manufacturing process bysolid-phase reaction.

FIG. 2 is a flow chart of a potassium humate manufacturing process bysolid-phase reaction.

FIG. 3 is a flow chart of a sodium humate manufacturing process bysolid-phase reaction.

FIG. 4 is a flow chart of an ammonium humate manufacturing process bysolid-phase reaction.

DETAILED DESCRIPTION OF THE INVENTION

Typical flow charts of the above reactions can be shown in FIGS. 1 to 4in which the major pieces of equipment are numerically marked andidentified as follows:

-   -   (1) Unloading hopper,    -   (2) Pneumatic conveyer,    -   (3) Premixing feed tank,    -   (4) Automatic weighing machine,    -   (5) Solid-phase reactor,    -   (6) Intermediate tank,    -   (7) Cyclone separator,    -   (8) Dust collector,    -   (9) Storage tank,    -   (10) Bagging machine,    -   (11) Blower,    -   (12) Ammonium hydroxide feeding tank,    -   (13) Dust collector, and    -   (14) Seal box.

FIG. 1 shows a flow chart of a caustic humate manufacturing process bysolid-phase reaction. The process includes the steps below:

1. Feed humic acid to a mixer (3) by pneumatic conveyor (2) to premixthe humic acid thoroughly.

2. Feed a fixed amount of the premixed humic acid into the solid-phasereactor (5) to agitate with a high-speed mixer.

3. Slowly add the solid-state alkali hydroxide into the mixer (5) at agiven rate.

4. Continue the high-speed agitation while proceed to complete mixing,reaction, and drying.

5. Unload the produced caustic humate salt into the intermediate tank(6) for cooling down, then transfer it to a storage tank (9) bypneumatic conveyor.

FIG. 2 is a flow chart of a potassium humate manufacturing process bysolid-phase reaction. The process includes the steps below:

1. Feed humic acid to a mixer (3) by pneumatic conveyor (2) to premixthe humic acid thoroughly.

2. Feed a fixed amount of the premixed humic acid into the solid-phasereactor (5) to agitate with a high-speed mixer.

3. Slowly add the solid-state potassium hydroxide into the mixer (5) ata given rate.

4. Continue the high-speed agitation while proceed to complete mixing,reaction, and drying.

5. Unload the produced potassium humate salt into the intermediate tank(6) to cool down, then transfer to a storage tank (9) by pneumaticconveyor.

FIG. 3 presents a flow chart of a sodium humate manufacturing process bysolid-phase reaction. The process includes the steps below:

1. Feed humic acid to a mixer (3) by pneumatic conveyor (2) to premixthe humic acid thoroughly.

2. Feed a fixed amount of the premixed humic acid into the solid-phasereactor (5) to agitate with a high-speed mixer.

3. Slowly add the solid-state sodium hydroxide into the mixer (5) at agiven rate.

4. Continue high speed agitation while proceed to complete mixing,reaction, and drying.

5. Unload sodium humate salt produced into intermediate tank (6) forcooling down, then send to storage tank (9) by pneumatic conveyor.

FIG. 4 shows a flow chart of an ammonium humate manufacturing process bysolid-phase reaction. The process includes the steps below:

1. Feed humic acid to a mixer (3) by pneumatic conveyor (2) to premixthe humic acid thoroughly.

2. Feed a fixed amount of the premixed humic acid into the solid-phasereactor (5) to agitate with a high speed mixer.

3. Spray a quantitative amount of ammonium hydroxide (12) uniformly intothe reactor (5) using high-pressure air.

4. Continue high-speed agitation while proceed to complete mixing,reaction, and drying.

5. Recover ammonia and water vapor evaporated during reaction forrecycling.

6. Unload ammonium humate salt produced into intermediate tank (6) forcooling down, then send to storage tank (9) by pneumatic conveyor.

EMBODIMENTS OF THE INVENTION

By employing a high-speed blender alone, the new process generates avigorous powder flow and a series of unit operations (includingcrushing, mixing as well as dissolution, neutralization, and evaporationdue to friction heat); the reaction temperature can thus beautomatically controlled. The embodiments of this invention include, butis not limited, to the following:

1. A process for producing potassium humate with a solid-phase fluidizedbed reaction. The mixture of potassium hydroxide containing 5 to 30%water and humic acid react in a high-speed intensive mixer running at300-2000 RPM. The agitation is multidirectional and free flowing, andpotassium humate is produced by means of high-speed agitation for mixingand neutralization reaction.

2. A process for producing sodium humate with a solid-phase fluidizedbed reaction. The mixture of sodium hydroxide containing 5 to 30% waterand humic acid react in high-speed intensive mixer running at 300-2000RPM. The agitation is multi-directional and free flowing, and sodiumhumate is produced by means of high-speed agitation for mixing andneutralization reaction.

3. A process for producing potassium and sodium humate with asolid-phase fluidized bed reaction. The mixture of potassium hydroxideand sodium hydroxide containing 5 to 30% water and humic acid react in ahigh-speed intensive mixer running at 300-2000 RPM. The agitation ismulti-directional and free flowing, and the mixture of sodium andpotassium humate is produced by means of high-speed agitation for mixingand neutralization reaction.

4. A process for producing ammonium humate with a solid-phase fluidizedbed reaction. This process uses a high-pressure spray mode to mixammonium hydroxide with humic acid in a high-speed intensive mixerrunning at 300-2000 RPM. The agitation is multi-directional and freeflowing, and ammonium humate is produced by means of high-speedagitation for mixing and neutralization reaction.

5. In accordance with Embodiments 1 to 4, a manufacturing processutilizes high-speed mixing to mix the mixture of solid containing lessthan 50% water and water-soluble solid or liquid-mist under fluidizingcondition.

6. In accordance with Embodiment 5, the humic acid includes, but is notlimit to, brown coal, peat, and weathering coal containing 5-90% humicacid.

7. In accordance with Embodiment 6, the raw materials of humic acid andcaustic powder shattered by a mixer can increase the reaction area.

8. Use a high-intensity mixer to achieve uniform quality, whileincreasing the contact area of the base and reducing the solid-statereaction time.

9. Utilize high-speed stirring action to create sufficient heat byfriction between reactant powders.

10. Utilize friction heat generated to liquefy solid alkali.

11. Potassium hydroxide is dissolved and ionized to K (or Na) ions whichreact with humic acid's COOH radicals ionized from humic acid.

12. Utilize the heat generated by the heat of reaction and friction heatto evaporate water and eliminate the energy required for drying.

13. Use the boiling point of water to make automatic temperatureregulation.

Advantages Over the Prior Art

There are many unique technical advantages of the present invention overtraditional methods of producing humic acid salts, such as those claimedby Patent CN101544675B. The most noticeable differences are:

1. This invention utilizes only high-speed agitation instead of thestandard fluidized-bed, which requires a large amount of gas to fluidizethe solid powder.

2. The present invention utilizes reaction heat and friction heat toevaporate excess water for keeping the reaction temperature and dryingproduct simultaneously. The conventional method requires a lot of extrasteam to maintain the reaction temperature.

3. The present invention is a dry process, achieving a complete reactionwith very little additional water. On the contrary, the traditionalmethod requires a lot of water to dissolve the caustic soda, beforemixing with the humic acid to form a paste state, followed by morecomplicated steps.

4. In the present invention, the flow pattern is very vigorous bythoroughly mixing the solid ingredients to achieve a rapid reaction,which can be completed in less than 20 minutes vs. 20-26 hours claimedby Patent CN101544675B.

5. Technical specification of the basic principle behind the presentinvention is due to (a) the large contact area of the ingredientscreated by the high-speed mixing and (b) the neutralization reactioncarried out both on the surface and on the inside of the powders. In themeantime, the temperature rises rapidly, causing the caustic flake tomelt and then to penetrate into the humic acid powders by osmoticpressure.

6. This invention uses the frictional heat and exothermic heat generatedby the reactants to control the reaction, to obtain more stable quality,and most importantly, to save a lot of energy from steam injection.Additionally, since all the chemical reactions take place underfluidizing conditions, any excess water contained in the mixture ofsolid phase (˜30% water) can be evaporated, thereby eliminating thesubsequent product drying and grinding steps.

EXAMPLES

Three experimental tests were conducted under the setups in accordancewith the concept described in this invention. Typical test conditionsand the results obtained are shown in the following examples:

Example 1

Equipment: High speed intensive mixer (Henschel brand)

Capacity: 200-500 Liter Agitator speed: 500-1500 RPM

Recipe: Humic acid (Purity 44%, Water content 24%): 100 kg

-   -   90% Potassium hydroxide: 13.3 kg (feed slowly)        Product Analysis:

Stirring Water Soluble Humic Time, min Content % Acid % 5 20.3 24.5 1018.7 26.8 15 16.4 29.2 20 14.3 31.5 30 13.1 35.9

Example 2

Equipment: High speed intensive mixer

Capacity: 200-500 Liter Agitator speed: 500-1500 RPM

Recipe: Humic acid (Purity 44%, Water content 24%): 100 kg

-   -   72% Sodium hydroxide: 12.6 kg (feed slowly)        Product Analysis:

Stirring Water Soluble Humic Time, min Content % Acid % 5 20.3 24.1 1018.7 26.5 15 16.4 28.9 20 14.8 31.1 30 12.7 35.5

Example 3

Equipment: High speed intensive mixer

Capacity: 200-500 Liter Agitator speed: 500-1500 RPM

Recipe: Humic acid (Purity 44%, Water content 24%): 100 kg

-   -   35% Ammonium hydroxide: 21 kg (under pressure spray mode)        Product Analysis:

Stirring Water Soluble Humic Time, min Content % Acid % 5 21.2 23.1 1018.9 25.5 15 16.4 27.8 20 14.3 30.2 30 13.1 35.1

The invention claimed is:
 1. A process for producing a dry humic acidsalt, the process comprising: feeding a humic acid source into a reactorcomprising a high-speed blender equipped with an agitator running at aspeed sufficient to generate fluidizing conditions in the reactor;feeding solid alkali hydroxide into the reactor; mixing the humic acidsource with the solid alkali hydroxide at conditions effective to meltthe solid alkali hydroxide; reacting the melted alkali hydroxide withhumic acid in the source to produce a humic acid salt; and drying thehumic acid salt to obtain a dry humic acid salt, wherein the mixing,reacting, and drying take place in the reactor.
 2. The process accordingto claim 1, which further comprises passing the dry humic acid salt to acyclone separator.
 3. The process according to claim 1, wherein thehumic acid source comprises brown coal, peat, or weathering coal.
 4. Theprocess according to claim 1, wherein the reaction is completed in lessthan 20 minutes.
 5. The process according to claim 1, wherein the alkalihydroxide is introduced into the reactor in flake or powder form.
 6. Theprocess according to claim 1, wherein the alkali hydroxide comprisespotassium hydroxide, sodium hydroxide, or both.
 7. The process accordingto claim 6, wherein the humic acid salt comprises potassium humate,sodium humate, or both.
 8. The process according to claim 1, wherein theagitator generates sufficient frictional heat to liquefy the alkalihydroxide.
 9. The process according to claim 8, which comprises usingthe heat of reaction and the frictional heat to dry the humic acid salt.